Liquid cooled heat sink for multiple separated heat generating devices

ABSTRACT

A liquid cooled heat sink has a thermal conduction plate and a liquid cooling module. The liquid cooling module is attached securely to the thermal conduction plate and has a distribution tank, a collection tank and a pipe assembly. The pipe assembly has multiple pipes of at least two different gauges and each pipe has a pipe inlet and a pipe outlet respectively secured to the distribution tank and the collection tank. Since a sum of the gauges is increased and each pipe need not to be coiled, an extra strong pumping system is not needed and design complexity is reduced.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to a heat sink, and more particularly to a liquid cooled heat sink for multiple heat generating devices placed at different position.

2. Description of the Related Art

A heat sink is very important to maintaining normal function of a machine or a computer system during prolonged operation. In the computer system, chips and power switches of the computer system generate heat during operation so heat sinks are mounted on surfaces of the chips and power switches to continuously cool the chips and the power switches together.

With reference to FIG. 11, a conventional liquid heat sink for a server system comprises a thermal conduction plate (60) and a single liquid pipe (70). The thermal conduction plate (60) has a contact surface (61) and a top surface (62). The contact surface (61) contacts multiple heat generating devices (80) of the server system. The liquid pipe (70) is a curved pipe having a constant diameter, is mounted on the top surface (62) and has an inlet (71) and an outlet (72). Coolant flows from the inlet (71) to the outlet (72) to take heat away from the thermal conduction plate (60), thereby cooling the heat generating devices (80).

However, the thermal conduction plate (60) has the following disadvantages:

1. To improve a cooling uniformity of the thermal conduction plate (60), the single liquid pipe (70) is coiled on the top surface (62), which causes an increased flow resistance. Therefore, a stronger pumping system is necessary to provide a larger pumping force so that the coolant flows smoothly in the liquid pipe (70), thus the cost is increased. Further, the liquid pipe (70) may be damaged when bending into shape causing reduced flow or rejection.

2. To uniformly covers the thermal conduction plate (60) with using the single and continuous liquid pipe (70), a length of the liquid pipe (70) has to long enough so that the liquid pipe (70) may be coiledly mounted on the thermal conduction plate (60). However, a temperature gradient of the coolant between the inlet (71) and the outlet (72) is increased when the liquid pipe (70) is long and is more coiled for improving cooling area. Generally, the inlet (71) has lower temperature than the outlet (72) has, which means that a heat exchanging ability at the inlet (71) remarkable. Therefore, the coolant draws more heat near the inlet (71) and less near the outlet (72) causing a heat gradient over the thermal conduction plate (60) to fluctuate. Therefore, layout of a motherboard is so limited that must be designed with referring to the heat gradient of the thermal conduction plate (60) thus let main heat generating devices (80) are located near the inlet (71) to increase a cooling ability. Hence, the aforementioned considerations increase complexity of designing component layout of the motherboard.

The present invention provides a liquid cooled heat sink to obviate or mitigate the shortcomings of the conventional heat sink.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide a liquid cooled heat sink having a plurality of different gauge pipes.

The liquid cooled heat sink has a thermal conduction plate and a liquid cooling module. The liquid cooling module is attached securely to the thermal conduction plate and has a distribution tank, a collection tank and a pipe assembly. The pipe assembly has multiple pipes of at least two different gauges and each pipe has a pipe inlet and a pipe outlet respectively secured to the distribution tank and the collection tank. Since a sum of the gauges is increased and each pipe need not to be coiled, an extra strong pumping system is not needed and design complexity is reduced.

Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction-with-the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a liquid cooled heat sink in accordance with the present invention;

FIG. 2 is a partially exploded perspective view of the liquid cooled heat sink in FIG. 1;

FIG. 3 is an exploded perspective view of a liquid cooling module of the liquid cooled heat sink in FIG. 1;

FIG. 4 is a top view of the liquid cooled heat sink in FIG. 1;

FIG. 5 is an exploded perspective view of a second embodiment of the liquid cooled heat sink in accordance with the present invention;

FIG. 6 is a perspective view of a third embodiment of the liquid cooled heat sink in accordance with the present invention;

FIG. 7 is a cross-sectional view of a first embodiment of a pipe having a smooth interior surface in FIG. 6;

FIG. 8 is a cross-sectional view of a second embodiment of a pipe having a zigzag interior surface in FIG. 6;

FIG. 9 is a cross-sectional view of a third embodiment of a pipe having a ragged interior surface in FIG. 6;

FIG. 10 is a cross-sectional view of a fourth embodiment of a pipe having a grid embedded interior surface in FIG. 6; and

FIG. 11 is a perspective view of a conventional liquid heat sink in accordance with the prior art.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1 and 5, a liquid cooled heat sink in accordance with the present invention comprises a thermal conduction plate (10) and a liquid cooling module.

With reference to FIGS. 2 to 4, the thermal conduction plate (10) may be rectangular and has a contact surface (11), a cooling surface (12) and two side edges. The contact surface (11) contacts multiple heat generating devices (50) shown as FIG. 4, such as a central processing unit of a server system, power switches or the like.

With further reference to FIG. 5, the liquid cooling module is attached securely to the thermal conduction plate (10), may be formed in the thermal conduction plate (10) or may be mounted securely on the cooling surface (12) of the thermal conduction plate (10). The liquid cooling module has a distribution tank (20, 101 a, 102 a), a collection tank (40, 101 c, 102 c) and a pipe assembly (30, 101 b, 102 b).

The distribution tank (20, 101 a, 102 a) is disposed adjacent to one of the side edges of the thermal conduction plate (10), may be a parallelepiped and has at least one distribution inlet (21) and multiple distribution outlets (22). The distribution tank (20, 101 a, 102 a) may be formed in or mounted on the thermal conduction plate (10) adjacent to one of the side edges of the thermal conduction plate (10).

The collection tank (40, 101 c, 102 c) is disposed adjacent to one of the side edges of the thermal conduction plate (10), may be rectangular and has multiple collection inlets (42) and at least one collection outlet (41). The collection tank (40, 101 c, 102 c) may be formed in or mounted on the thermal conduction plate (10) adjacent to the other one of the side edges of the thermal conduction plate (10).

The pipe assembly (30, 101 b, 102 b) has multiple pipes. The pipes are separately formed in or mounted on the thermal conduction plate (10) and of at least two different gauges and each pipe has a pipe inlet (31) and a pipe outlet (32). With further reference to FIGS. 6-10, the pipes may have different interior diameters to define the at least two different gauges or may have different morphology of interior surfaces of the pipes. For instance, the pipes may have a smooth interior surface (301), a zigzag interior surface (302), a ragged interior surface (303) or a grid embedded interior surface (304) to form the different gauges.

A pipe assembly (30, 101 b, 102 b) having three pipes may have two pipes having a same gauge and one that is different. Alternatively, the pipes may each be formed to have non-identical gauges. The pipe inlet (31) of each pipe is securely mounted with one of the distribution outlets (22) and the pipe outlet (32) of each pipe is securely mounted with one of the collection inlets (42). Thus a passage of each pipe communicates with the distribution tank (20, 101 a, 102 a) and the collection tank (40, 101 c, 102 c).

In a first embodiment shown as FIGS. 1-4 of the present invention, the liquid cooling module is mounted securely on the cooling surface (12). The pipes with different gauges are separately mounted on the cooling surface (12). In the first embodiment, longer pipes have larger gauges. The pipes may be substantially U-shaped for mounting on the distribution tank (20) and the collection tank (40).

In a second embodiment shown as FIG. 5, the liquid cooling module is formed in the thermal conduction plate (10). For ease of manufacturing, the thermal conduction plate (10) may have a first plate (101) and a second plate (102). The first plate (101) has an inner surface having a recessed distribution tank (101 a), a recessed collection tank (101 c) and a recessed pipe assembly (101 b) corresponding respectively to the distribution tank (20), collection tank (40) and multiple pipes (30). The recessed pipe assembly (101 b) has multiple recessed pipes, each recessed pipes has two pipe ends respectively communicating with the recessed distribution tank (101 a) and the recessed collection tank (101 c). Accordingly, the second plate (102) is shaped corresponding to and securely mounted with the first plate (101) and has an inner surface. The inner surface of the second plate (102) is mounted securely on the inner surface of the first plate (101) and has a recessed distribution tank (102 a), a recessed collection tank (102 c) and a recessed pipe assembly (102 b) that respectively correspond to and communicate with the distribution tank (101 a), the collection tank (101 c) and the pipe assembly (101 b) to from the pipe assembly in the thermal conduction plate (10). When assembling, the inner surfaces of the first and second plates (101, 102) are mounted securely, thereby the distribution tank (101 a, 102 a), the collection tank (101 c, 102 c) and the pipe assembly (101 b, 102 b) are then formed in the thermal conduction plate (10). Furthermore, different gauges in the second embodiment can be formed by defining depths of the recessed pipes of the pipe assembly (101 b, 102 b).

Because the pipes of the pipe assembly (30, 101 b, 102 b) may have different gauges and are separately mounted on or formed in the thermal conduction plate (10), the pipes are shorter and have less complex curves than in prior art. Hence, stronger pumping system requirements and uniformity problems in the conventional liquid heat sink are resolved. Furthermore, a sum of the gauges of the disclosed embodiments is increased over the prior art, a flow rate is increased thereby the heat transformation efficiency is also improved according to the following equation:

{dot over (Q)}=ρ{dot over (v)}C _(p) ΔT

where,

{dot over (Q)} is derivative of heat by time;

C_(p) is specific heat of coolant;

{dot over (v)} is flow rate;

ρ is density of coolant; and

ΔT is temperature difference.

As disclosed above, since the present invention has higher flow rate, a larger {dot over (Q)} is derived due to a rise in “{dot over (v)}”.

In summary, the liquid cooled heat sink has advantages as following:

1. Because the pipe assembly (30, 101 b, 102 b) has multiple pipes, the pipes in the present disclosure are then able to be separately mounted uniformly on the thermal conduction plate (10) without over coiled. Therefore, the coolant may smoothly flow in the pipes even without a stronger pumping system.

2. A higher cooling ability ({dot over (Q)}) is achieved since a higher flow rate ({dot over (v)}) is achieved from an increased sum of the cross-section areas of the pipes. Hence, the present disclosure is perfectly suitable to be used for apparatuses having a purity of heat generating devices (50) that are spread allocated on the apparatuses.

3. Although temperature difference of the coolant existed at the pipe inlet (31) and pipe outlet (32) of a longer pipe, thereby may reduce the cooling ability of the present disclosure. To overcome this problem, the present disclosure increases a passage cross-section of the longer pipe so as to increase flow rate thereof. Hence, the temperature difference of the coolant at the pipe inlet (31) and outlet (32) become non-obvious and an uniform cooling ability is available.

Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only. Changes may be made in detail, especially in matters of shape, size and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

1. A liquid cooled heat sink for multiple separated heat generating devices comprising: a thermal conduction plate having a contact surface thermal contacting with the multiple separated heat generating devices; a cooling surface; and two side edges; and a liquid cooling module being attached securely to the thermal conduction plate and having a distribution tank being disposed adjacent to one of the side edges of the thermal conduction plate and having at least one distribution inlet and multiple distribution outlets; a collection tank being located adjacent to one of the side edges of the thermal conduction plate and having multiple collection inlets and at least one collection outlet; and a pipe assembly having multiple pipes of at least two different gauges and each pipe having a pipe inlet, a pipe outlet respectively secured to the distribution outlets and the collection inlets, thereby communicating with the distribution tank and the collection tank.
 2. The liquid cooled heat sink as claimed in claim 1, wherein the pipes have at least two different interior diameters to form the at least two different gauges.
 3. The liquid cooled heat sink as claimed in claim 1, wherein the pipes have different morphology of interior surfaces of the pipes to form the at least two gauges, wherein at least one pipe has a zigzag interior surface.
 4. The liquid cooled heat sink as claimed in claim 1, wherein the pipes have different morphology of interior surfaces of the pipes to form the at least two gauges, wherein at least one of the pipes has a ragged interior surface.
 5. The liquid cooled heat sink as claimed in claim 3, wherein the pipes have different morphology of interior surfaces of the pipes to form the at least two gauges, wherein at least one of the pipes has a ragged interior surface.
 6. The liquid cooled heat sink as claimed in claim 1, wherein the pipes have different morphology of interior surfaces of the pipes to form the at least two gauges, wherein at least one of the pipes has a grid embedded interior surface.
 7. The liquid cooled heat sink as claimed in claim 3, wherein the pipes have different morphology of interior surfaces of the pipes to form the at least two gauges, wherein at least one of the pipes has a grid embedded interior surface.
 8. The liquid cooled heat sink as claimed in claim 5, wherein the pipes have different morphology of interior surfaces of the pipes to form the at least two gauges, wherein at least one of the pipes has a grid embedded interior surface.
 9. The liquid cooled heat sink as claimed in claim 8, wherein the liquid cooling module is mounted securely on the cooling surface of the thermal conduction plate.
 10. The liquid cooled heat sink as claimed in claim 8, wherein the liquid cooling module is formed in the thermal conduction plate.
 11. The liquid cooled heat sink as claimed in claim 1, wherein the thermal conduction plate has two plates each having an inner surface, the inner surface of each plate having a recessed distribution tank, a recessed collection tank and a recessed pipe assembly that are corresponding respectively to the distribution tank, collection tank and pipes, wherein depths of the recessed pipes correspond to gauges of the pipes.
 12. The liquid cooled heat sink as claimed in claim 1, wherein the pipes of the pipe assembly have different lengths, and longer pipes have larger gauges.
 13. The liquid cooled heat sink as claimed in claim 2, wherein the pipes of the pipe assembly have different lengths, and longer pipes have larger gauges.
 14. The liquid cooled heat sink as claimed in claim 3, wherein the pipes of the pipe assembly have different lengths, and longer pipes have larger gauges.
 15. The liquid cooled heat sink as claimed in claim 4, wherein the pipes of the pipe assembly have different lengths, and longer pipes have larger gauges.
 16. The liquid cooled heat sink as claimed in claim 5, wherein the pipes of the pipe assembly have different lengths, and longer pipes have larger gauges.
 17. The liquid cooled heat sink as claimed in claim 6, wherein the pipes of the pipe assembly have different lengths, and longer pipes have larger gauges.
 18. The liquid cooled heat sink as claimed in claim 7, wherein the pipes of the pipe assembly have different lengths, and longer pipes have larger gauges.
 19. The liquid cooled heat sink as claimed in claim 8, wherein the pipes of the pipe assembly have different lengths, and longer pipes have larger gauges.
 20. The liquid cooled heat sink as claimed in claim 9, wherein the pipes of the pipe assembly have different lengths, and longer pipes have larger gauges. 